If the owner of a property agrees to allow someone to stay there in exchange for rent, a legal relationship of landlord / tenant is immediately created. (Different rules apply if the owner also lives there - see the later section on lodgings.

Almost all new private tenancies that started after 28 February 1997 are called 'Assured Shorthold Tenancies'. These were set up by the Housing Act 1988 and were modified by the 1996 Housing Act. They state how such tenancies start and how they can be ended.

Even if there is nothing in writing, once someone moves in, a tenancy still exists and the same basic rules apply to ending the tenancy as if it was started with a written tenancy agreement.